HOTS Questions for Class 10 Science Chapter 9 Heredity and Evolution

HOTS Questions for Class 10 Science Chapter 9 Heredity and Evolution

These Solutions are part of HOTS Questions for Class 10 Science. Here we have given HOTS Questions for Class 10 Science Chapter 9 Heredity and Evolution

Question 1.
Observe the diagram carefully. What does it depict ? Identify the parts shown by lines.
HOTS Questions for Class 10 Science Chapter 9 Heredity and Evolution image - 1
Answer:
Reconstruction of fossil bird Archaeopteryx.

  1. Claw
  2. Free fingers
  3. Beak
  4. Teeth
  5. Tail
  6. Feathers

More Resources

Question 2.
Name the organism in which feathers appeared for the first time.
Answer:
Members of Dromaesaur family which were small dinosaurs.

Question 3.
Which one is the edible part in Kale, Kohlrabi, Broccoli, Brussel’s Sprout, Cabbage and Cauliflower ?
Answer:
Kale — Leaves,
Kohlrabi — Swollen stem,
Broccoli — Immature green flowers,
Brussel’s Sprout — Axillary buds,
Cabbage — Terminal bud,
Cauliflower — Immature inflorescence of sterile flowers.

Question 4.
Give an example where temperature determines the sex of the new bom.
Answer:

  1. Chrysema picta (a turtle). Temperature above 33°C produces females and below 28°C males.
  2. Agama agama (a lizard). High temperature produces males.

Question 5.
Name a recessive trait which is quite common in human beings.
Answer:
Blood group O (I°I°).

Question 6.
Why is variation beneficial for the species but not necessarily for the individual ? (CBSE Foreign 2010)
Answer:
Preadaptation is a variation which under normal conditions is of no advantage to the individual bearing it. However, it becomes highly useful in survival under changed environment, e.g, heat wave in temperate environment, insecticide or antibiotic resistance.

Hope given HOTS Questions for Class 10 Science Chapter 9 Heredity and Evolution are helpful to complete your science homework.

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RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C

RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C

These Solutions are part of RS Aggarwal Solutions Class 6. Here we have given RS Aggarwal Solutions Class 6 Chapter 10 Ratio, Proportion and Unitary Method Ex 10C.

Other Exercises

Question 1.
Solution:
Cost of 14 m of cloth = Rs. 1890
Cost of 1 m = Rs. \(\\ \frac { 1890 }{ 14 } \)
and cost of 6 m = Rs. \(\\ \frac { 1890\times 6 }{ 14 } \)
= Rs. 135 x 6
= Rs. 810

Question 2.
Solution:
Cost of 1 dozen or 12 soaps = Rs. 285.60
Cost of 1 soap = Rs. \(\\ \frac { 285.60 }{ 12 } \)
Cost of 15 soaps = Rs. \(\\ \frac { 285.60\times 15 }{ 12 } \)
= Rs. 357.00

Question 3.
Solution:
Cost of 9 kg of rice = Rs. 327.60
Cost of 1 kg = Rs. \(\\ \frac { 327.60 }{ 9 } \)
and cost of 50 kg = Rs. \(\\ \frac { 327.60\times 50 }{ 9 } \)
= Rs. 36.40 x 50
= Rs. 1820

Question 4.
Solution:
Weight of 22.5 metres of the iron rod: = 85.5 kg
Weight of 1 metre of the iron rod
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q4.1

Question 5.
Solution:
Quantity of oil in 15 tins = 234 kg
Quantity of oil in 1 tin = \(\\ \frac { 234 }{ 15 } \) kg
Quantity of oil in 10 tins
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q5.1

Question 6.
Solution:
Distance covered by the car in 12 litres of diesel = 222 kms
Distance covered by the car in 1 litre of diesel = \(\\ \frac { 222 }{ 12 } \) km
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q6.1

Question 7.
Solution:
Charges of 25 tonnes of weight = Rs. 540
charges of 1 ton = Rs.\(\\ \frac { 540 }{ 25 } \)
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q7.1

Question 8.
Solution:
Weight of copper in 4.5 g of alloy = 3.5g
Weight of copper in 1 g of alloy
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q8.1

Question 9.
Solution:
In Rs. 87.50, the inland letter are purchased = 35
In Re. 1, letters can be purchased
= \(\\ \frac { 35 }{ 87.50 } \)
and in Rs. 315, letters can be purchased
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q9.1

Question 10.
Solution:
4 dozen = 4 x 12 = 48 bananas
In Rs. 104, banana are purchased = 48
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q10.1

Question 11.
Solution:
In Rs. 22770, chairs are purchased =18
In Re. 1, chairs will be purchased
= \(\\ \frac { 18 }{ 22770 } \)
and in Rs. 10120, chairs will be
purchased = \(\\ \frac { 18\times 10120 }{ 22770 } \)
= 8

Question 12.
Solution:
(i) A car travels 195 km distance in = 3 hours
It will travel 1 km distance in = \(\\ \frac { 3 }{ 195 } \) hr.
and it will travel 520 km distance in
= \(\\ \frac { 3\times 520 }{ 195 } \)
= 8 hr
(ii) A car travels in 3hr = 195 km
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q12.1

Question 13.
Solution:
(i) A laborer earn in 12 days = Rs. 1980
He will earn in 1 day = Rs. \(\\ \frac { 1980 }{ 12 } \)
and he will earn in 7 days
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q413.1

Question 14.
Solution:
(i) Weight of 65 books = 13 kg
Then weight of 1 book = \(\\ \frac { 13 }{ 65 } \) kg
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q14.1

Question 15.
Solution:
Number of boxes needed for 6000 pens = 48
Number of boxes needed for 1 pen 48 = \(\\ \frac { 48 }{ 6000 } \)
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q15.1

Question 16.
Solution:
Clearly, less workers will build the wall in more days.
And, more workers will build the wall in less days.
24 workers can build the wall in 15 days
1 worker can build the wall in (15 x 24) days
(less worker, more days)
9 workers will build the wall in
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q16.1

Question 17.
Solution:
Men needed to finish a piece of work in 26 days = 40
Men needed to finish a piece of work in 1 day = 40 x 26 (less days, more men)
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q17.1

Question 18.
Solution:
Clearly, less men will take more days to consume the food.
And, more men will take less days to consume the food.
550 men have provisions for 28 days
1 men has provisions for (28 x 550) days [less men, more days]
700 men will have provisions for
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q18.1

Question 19.
Solution:
Clearly, less persons will consume the rice in more days.
And more persons will consume the rice in less days.
60 persons consume the bag of rice in 3 days.
1 person will consume the bag of rice in
(3 x 60) days (less persons, more days)
18 persons will consume the bag of rice
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10C Q19.1

Hope given RS Aggarwal Solutions Class 6 Chapter 10 Ratio, Proportion and Unitary Method Ex 10C are helpful to complete your math homework.

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RS Aggarwal Class 6 Solutions Chapter 16 Triangles Ex 16B

RS Aggarwal Class 6 Solutions Chapter 16 Triangles Ex 16B

These Solutions are part of RS Aggarwal Solutions Class 6. Here we have given RS Aggarwal Solutions Class 6 Chapter 16 Triangles Ex 16B

Other Exercises

Objective questions
Mark against the correct answer in each of following.

Question 1.
Solution:
(c) ∵ It has three sides and three angles i.e. six.

Question 2.
Solution:
(b) ∵ Sum of three angles of a triangle is 180°.

Question 3.
Solution:
(b) ∵ Largest angle
\(=\frac { { 180 }^{ O }\times 4 }{ 2+3+4 } =\frac { { 180 }^{ O }\times 4 }{ 9 } \)
= 80°

Question 4.
Solution:
(d) ∵ A triangle has 180° and if two angles are complementary i.e. sum of two angles is 90°, then third angle will be 180° – 90° = 90°.

Question 5.
Solution:
(c) ∵ Sum of three angles is 180° and sum of two equal angles = 70° + 70° = 140°, then third angle will be 180°- 140° = 40°.

Question 6.
Solution:
(c) ∵ A scalene triangle has different sides.

Question 7.
Solution:
In an isosceles ∆ABC, ∠B = ∠C and bisector of ∠B and ∠C meet at O and ∠A = 40°
RS Aggarwal Class 6 Solutions Chapter 16 Triangles Ex 16B Q7.1
RS Aggarwal Class 6 Solutions Chapter 16 Triangles Ex 16B Q7.2

Question 8.
Solution:
Side of a triangle are in the ratio 3:2:5 and perimeter = 30 m
Length of longest side = \(\frac { 30\times 5 }{ 3+2+5 } \)
= \(\frac { 30\times 5 }{ 10 } \) cm
= 15 cm (b)

Question 9.
Solution:
Two angles of a triangle are 30° and 25° But sum of three angles of a triangle – 180°
Third angle = 180° – (30 + 25°)
= 180° – 55° = 125° (d)

Question 10.
Solution:
Each angles of an equilateral triangle = 60°
as each angle of an equilateral triangle are equal
Each angle = \(\\ \frac { 180 }{ 3 } \) = 60° (c)

Question 11.
Solution:
In the figure, P lies on AB
Its lies on the ∆ABC (c)

Hope given RS Aggarwal Solutions Class 6 Chapter 16 Triangles Ex 16B are helpful to complete your math homework.

If you have any doubts, please comment below. Learn Insta try to provide online math tutoring for you.

RD Sharma Class 8 Solutions Chapter 7 Factorizations Ex 7.4

RD Sharma Class 8 Solutions Chapter 7 Factorizations Ex 7.4

These Solutions are part of RD Sharma Class 8 Solutions. Here we have given RD Sharma Class 8 Solutions Chapter 7 Factorizations Ex 7.4

Other Exercises

Factorize each of the following expressions :
Question 1.
qr-pr + qs – ps
Solution:
qr- pr + qs-ps
Arranging in suitable groups = r(q-p) +s (q-p)    {(q – p) is common}
= (q-p) (r + s)

Question 2.
p2q -pr2-pq + r2
Solution:
p2q -pr2-pq + r2
= p2q -pq-pr2 + r2 (Arranging in group)
= pq(p- 1)-r2(p-1) {(p – 1) is common}
= (p – 1) (pq – r2)

Question 3.
1 + x + xy + x2y
Solution:
1 + x + xy + x 2y
= 1 (1 + x) +xy (1 +x)
= (1 + x) (1 + xy) {(1 + x) is common}

Question 4.
ax + ay – bx – by
Solution:
ax + ay – bx – by
= a (x + y) – b (x + y)   {(x + y) is coinmon}
= (x+y) (a- b)

Question 5.
xa2 + xb2 -ya2 – yb2
Solution:
xa2 + xb2 – ya2 – yb2
= x (a2 + b2) -y (a2 + b2)   {(a2 + b2) is common}
= {a2 + b2) (x -y)

Question 6.
x2 + xy + xz + yz
Solution:
x2 + xy + xz + yz
= x (x + y) + z(x + y) {(x + y) is common}
= (x + y) (x + z)

Question 7.
2ax + bx + 2ay + by
Solution:
2ax + bx + 2ay + by
= x {2a + b) + y (2a + b)      {(2a + b) is common}
= (2a + b) (x + y)

Question 8.
ab- by- ay +y2
Solution:
ab – by – ay + y2
= b(a-y)-y(a-y)    {(a -y) is common}
= (a-y) (b – y)

Question 9.
axy + bcxy -az- bcz
Solution:
axy + bcxy – az – bcz
= xy (a + bc) – z (a + bc)       {(a + bc) is common}
= (a + bc) (xy – z)

Question 10.
lm2 – mn2 – lm + n2
Solution:
lm2 – mn2 – lm + n2
= m (lm – n2)- 1 (lm – n2)  {(lm – n2) is common}
= (lm – n2) (m – 1)

Question 11.
x– y+ x – x2y2
Solution:
x3 -y2 + x – x2y2
⇒ x3 + x – x2y2 – y2
= x(x2+ 1)-y2(x2+ 1)        {(x2 + 1) is common}
= (x2 + 1) (x -y2)

Question 12.
6xy + 6 – 9y – 4x
Solution:
6xy + 6 – 9y – 4x
= 6 xy – 4x – 9y + 6
2x (3y – 2) – 3 (3y – 2)    {(3y – 2) is common}
= (3y-2) (2x – 3)

Question 13.
x22ax – 2ab + bx
Solution:
x2 – 2ax – 2ab + bx
⇒ x2 – 2ax + bx – 2ab
= x (x – 2a) + b (x – 2a)   {(x – 2a) is common}
= (x – 2a) (x + b)

Question 14.
x3 – 2x2y + 3xy2 – 6y3
Solution:
x3 – 2x2y + 3xy2 – 6y3
= x2 (x – 2y) + 3y2 (x – 2y)     {(x – 2y) is common}
= (x – 2y) (x2 + 3y2)

Question 15.
abx2 + (ay – b) x-y
Solution:
abx2 + (ay – b) x-y
= abx2 + ayx – bx -y 
= ax (bx + y) – 1 (bx + y)               {(bx +y) is common}
= (bx + y) (ax – 1)

Question 16.
(ax + by)2 + (bx – ay)2
Solution:
(ax + by)2 + (bx – ay)2
= a2x2 + b2y2 + 2abxy + b2x2 + a2y2 – 2abxy
= a2x2 + b2y2 + b2x2 + a2y2
= a2x2 + b2x2 + a2y2 + by2
= x2 (a2 + b2) + y2 (a2 + b2)         {(a2 + b2) is common}
= (a2 + b2) (x2 + y2)

Question 17.
16 (ab)3 -24 (a- b)2
Solution:
16 (a – b)3 -24 (a- b)2
HCF of 16, 24 = 8
and HCF of (a – b)3, (a – b)2 = (a – b)2
∴16 (a – b)3 – 24 (a – b)2
= 8 (a-b)2 {2 (a-b)- 3}
{8 (a – b)2 is common}
= 8 (a – b)2 (2a – 2b – 3)

Question 18.
ab (x2 + 1) + x (a2 + b2)
Solution:
ab (x2 + 1) + x (a2 + b2)
= abx2 + ab + a2x + b2x
= abx2 + b2x + a2x + ab
= bx (ax + b) + a (ax + b)  {(ax + b) is common}
= (ax + b) (bx + a)

Question 19.
a2x2 + (ax2 + 1) x + a
Solution:
a2x2 + (ax2 + 1) x + a
= a2x2 + ax3 + x + a
= ax3 + a2x2 + x + a
= ax2 (x + a) + 1 (x + a) {(x + a) is common}
= (x + a) (ax2 + 1)

Question 20.
a(a- 2b -c) + 2bc
Solution:
a(a- 2b -c) + 2bc
= a2– 2ab -ac +2bc
= a (a – 2b) – c (a – 2b) {(a – 2b) is common}
= (a – 2b) (a – c)

Question 21.
a (a + b – c)- bc
Solution:
a (a + b – c) – bc
= a2 + ab – ac – bc
= a (a + b) – c (a + b)   {(a + b) is common}
= (a + b) (a – c)

Question 22.
x2 – 11xy – x +11y
Solution:
x2 – 11xy-x + 11y
= x2 -x – 11 xy + 11 y
= x (x – 1) – 11y (x – 1)   {(x – 1) is common}
= (x- 1) (x- 11y)

Question 23.
ab – a – b + 1
Solution:
ab – a-b + 1
= a (b – 1) – 1 (b – 1)    {(b – 1) is common}
= (b – 1) (a – 1)

Question 24.
x2 + y – xy – x
Solution:
x2 + y – xy – x
= x2 – x- xy + y
= x (x – 1) – y (x – 1)   {(x – 1) is common}
= (x- 1) (x-y)

Hope given RD Sharma Class 8 Solutions Chapter 7 Factorizations Ex 7.4 are helpful to complete your math homework.

If you have any doubts, please comment below. Learn Insta try to provide online math tutoring for you.

RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4

RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4

These Solutions are part of RD Sharma Class 8 Solutions. Here we have given RD Sharma Class 8 Solutions Linear Equations in One Variable Ex 9.4

Other Exercises

Question 1.
Four-fifth of a number is more than three-fourth of the number by 4. Find the number.
Solution:
Let the required number = x
Then four-fifth of the number = \(\frac { 4 }{ 5 }\)x
and three- fourth =  \(\frac { 3 }{ 4 }\)x
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 1

Question 2.
The difference between the squares of two consecutive numbers is 31. Find the numbers.
Solution:
Let first number = x
There second number = x + 1
∴ According to the condition :
(x + 1)2 – (x)2 = 31
⇒ x2 + 2x + 1 – x2 = 31
⇒ 2x = 31 – 1 = 30 30
⇒ x =  \(\frac { 30 }{ 2 }\) = 15
∴  First number = 15
and second number = 15 + 1 = 16
Hence numbers are 15, 16
Check : (16)2 – (15)2 = 256 – 225 = 31
Which is given
∴  Our answer is correct.

Question 3.
Find a number whose double is 45 greater than its half.
Solution:
Let the required number = x
Double of it = 2x
and half of it =  \(\frac { x }{ 2 }\)
According to the condition :
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 2
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 3

Question 4.
Find a number such that when 5 is subtracted from 5 times the number, the result is 4 more than twice the number.
Solution:
Let the required number = x 5
times of it = 5x
twice of it = 2x
According to the condition :
5x – 5 = 2x + 4
⇒ 5x – 2x = 4 + 5
⇒ 3x = 9
⇒ x =\(\frac { 9 }{ 3 }\)   = 3
Required number = 3
Check :3 x 5-5 = 2×3+4
⇒  15-5 = 6 + 4
⇒ 10= 10
Which is true. Therefore our answer is correct.

Question 5.
A number whose fifth part increased by 5 is equal to its fourth part diminished by 5. Find the number.
Solution:
Let the number = x
Then fifth part increased by 5 = \(\frac { x }{ 5 }\) + 5
Fourth part diminished by 5 = \(\frac { x }{ 4 }\)  – 5
According to the condition :
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 4
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 5

Question 6.
A number consists of two digits whose sum is 9. If 27 is subtracted from the number, its digits are reversed. Find the number.
Solution:
Sum of two digits = 9
Let units digit = x
Then tens digit = 9 – x
and number = 10 (9 – x) + x
= 90 – 10x + x = 90 -9x
On reversing the digits,
Units digit = 9 -x tens digit = x
and number = 10 (x) + 9 – x
= 10x + 9- x = 9x + 9
According to the condition :
90 – 9x – 27 = 9x + 9
⇒ 9x + 9x = 90 – 27-9
⇒ 18x = 90- 36 = 54
⇒ x =\(\frac { 54 }{ 18 }\) = 3
Number = 90 – 9x = 90 – 9 x 3 = 90 – 27 = 63
Check : 63 – 27 = 36 (Whose digits are reversed)
Which is true. Therefore our answer is correct.

Question 7.
Divide 184 into two parts such that one- third of one part may exceed one seventh of another part by 8.
Solution:
Sum of two parts = 184
Let first part = x
Then second part = 184 – x
According to the condition :
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 6

Question 8.
The numerator of a fraction is 6 less than the denominator. If 3 is added to the numerator, the fraction is equal to \(\frac { 2 }{ 3 }\) . What is the original fraction equal to ?
Solution:
Let denominator of the original fraction = x
Then numerator = x – 6
and fraction = \(\frac { x-6 }{ x }\)
According to the condition :
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 7
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 8

Question 9.
A sum of Rs. 800 is in the form of denominations of Rs. 10 and Rs. 20. If the total number of notes be 50, find the number of notes of each type.
Solution:
Total amount = Rs. 800
Total number of notes = 50
Let number of notes of Rs. 10 = x
Then number of notes of Rs. 20 = 50 – x
According to the condition, x x 10 + (50-x) x 20 = 800
⇒  10x + 1000 – 20x = 800
⇒  -10x = 800- 1000 = -200
⇒ x =   \(\frac { -200 }{ -10 }\) = 20
∴ Number of 10-rupees notes = 20
and number of 20-rupees notes = 50-20 = 30
Check : 20 x 10 + 30 x 20
= 200 + 600 = 800
Which is true. Therefore our answer is correct.

Question 10.
Seeta Devi has Rs. 9 in fifty-paise and twenty five-paise coins. She has twice as many twenty-five paise coins as she has fifty-paise coins. How many coins of each kind does she have ?
Solution:
Total amount = Rs. 9
Let fifty paise coins = x
Then twenty-five paise coins = 2x
According to the condition :
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 9
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 10

Question 11.
Sunita is twice as old as Ashima. If six years is subtracted from Ashima’s age and four years added to Sunita’s age, then Sunita will be four times Ashima’s age. How old were they two years ago ?
Solution:
Let age of Ashima = x
Then age of Sunita = 2x
According to the condition :
4 (x – 6) = 2x + 4
⇒  4x-24 = 2x + 4
⇒ 4x-2x = 4 + 24
⇒  2x = 28
⇒ x = \(\frac { 28 }{ 2 }\) = 14
∴  Sunita’s present age = 2x = 2 x 14 = 28 years
and Ashima’s age = 14 years
Two years ago,
Age of Sunita = 28 – 2 = 26 years
and age of Ashima =14-2 = 12 years

Question 12.
The ages of Sonu and Monu are in the ratio 7 : 5. Ten years hence, the ratio of their ages will be 9 : 7. Find their present ages.
Solution:
Ratio in the present ages of Sonu and Monu = 7:5
Let age of Sonu = 7x years
and age of Monu = 5x years
10 years hence,
the age of Sonu = 7x + 10 years
and age of Monu = 5a + 10 years
According to the condition :
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 11

Question 13.
Five years ago a man was seven times as old as his son. Five years hence, the father will be three times as old as his son. Find their present ages.
Solution:
5 years ago,
Let age of son = x years
Then, age of father = 7a years
Present age of son = x + 5 years
and age of father = 7x + 5 years
5 years hence,
age of son = x + 5 + 5= x+10
and age of father = 7x + 5 + 5 = 7x + 10
According to the condition :
7x + 10 = 3 (x + 10)
⇒  7x + 10 = 3x + 30
⇒  7x -3x= 30 – 10 = 20
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 12

Question 14.
I am currently 5 times as old as my son. In 6 years time I will be three times as old as he will be then. What are our ages now ?
Solution:
Let present age of my son = x years
Then my age = 5x years
After 6 years,
my age will be = 5x + 6
and my son’s age = x + 6
According to the condition
5x + 6 = 3 (x + 6)
⇒ 5x+ 6 = 3x+ 18
⇒ 5x – 3x = 18 – 6 ⇒ 2x = 12
⇒ x = 6
∴ Present my age = 5x = 5 x 6 = 30 years
and my son’s age = 6 years

Question 15.
I have Rs. 1000 in ten and five rupees notes. If the number of ten rupees notes that I have is ten more than the number of five rupees notes, how many notes do I have in each denomination ?
Solution:
Total amount = Rs. 1000
Let the number of five rupee notes = x
∴ Ten rupees notes = x + 10
According to the condition,
(x + 10) x 10 + 5 x x x = 1000
⇒ 10a + 100 + 5a = 1000
⇒  15a = 1000- 100 = 900
⇒ x = \(\frac { 900 }{ 15 }\) = 60
∴  Number of five rupees notes = 60
and number of ten rupees notes = 60 + 10 = 70

Question 16.
At a party, colas, squash anjd fruit juice were offered to guests. A fourth of the guests drank colas, a third drank squash, two fifths drank juice and just three did not drink any thing. How many guests were in all ?
Solution:
Let total number of guests = x
Guests who drank colas = \(\frac { x }{ 4 }\)
Guests who drank squash = \(\frac { x }{ 3 }\)
Guests who drank juice = \(\frac { 2 }{ 5 }\) x
Guest who drank none of these = 3
According to the condition :
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 13

Question 17.
There are 180 multiple choice questions in a test. If a candidate gets 4 marks for every correct answer and for every unattempted or wrongly answered question one mark is deducted from the total score of correct answers. If a candidate scored 450 marks in the test, how many questions did he answer correctly ?
Solution:
Number of total questions = 180
Let the candidate answers questions correctly = x
∴ Uncorrect or unattended questions =180 -x
total score he got = 450
According to the condition
x x 4-(180-x) x 1 =450
⇒ 4x – 180 + x = 450
⇒ 5x = 450+ 180 = 630
⇒ x =\(\frac { 630 }{ 5 }\) = 126
Number of question which answered correctly = 126

Question 18.
A labourer is engaged for 20 days on the condition that he will receive Rs. 60 for each day, he works and he will be fined Rs. 5 for each day, he is absent, If he receives Rs. 745 in all, for how many days he remained absent ?
Solution:
Total number of days = 20
Let number of days he worked = x
Then number of days he remained absent = 20 – x
According to the condition :
x x 60 – (20 – x) x 5 = 745
⇒  60x- 100 + 5x = 745
⇒  65x = 745 + 100 = 845
⇒  x = \(\frac { 845 }{ 65 }\) = 13
∴ Number of days he worked =13 days
and number of days he remained absent = 20 – 13 = 7 days.

Question 19.
Ravish has three boxes whose total weight is 60 \(\frac { 1 }{ 2 }\) kg. Box B weighs 3\(\frac { 1 }{ 2 }\) kg more it than A and box C weighs 5\(\frac { 1 }{ 3 }\) kg more than box B. Find the weight of box A.
Solution:
Total weight of three boxes = 60\(\frac { 1 }{ 2 }\) kg.
Let weight of box A = x kg.
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 14
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 15

Question 20.
The numerator of a rational number is 3 less than the denominator. If the denominator is increased by 5 and the numerator by 2, we get the rational number \(\frac { 1 }{ 2 }\). Find the rational number.
Solution:
Let denominator of the given rational number = x
Then numerator = x – 3
∴ Rational number =\(\frac { x – 3 }{ x }\)
According to the condition :
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 16

Question 21.
In a rational number, twice the numerator is 2 more than the denominator. If 3 is added to each, the numerator and the denominator, the new fraction is \(\frac { 2 }{ 3 }\) . Find the original number.
Solution:
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 17

Question 22.
The distance between two stations is 340 km. Two trains start simultaneously from these stations on parallel tracks to cross each other. The speed of one of them is greater than that of the other by 5 km/ hr. If the distance between the two trains after 2 hours of their start is 30 km, find the speed of each train.
Solution:
Distance between two stations = 340 km.
Let the speed of the first train = x km/hr.
Then speed of second train = (x + 5) km/h.
Time = 2 hours
Distance travelled by the first train in 2 hours = 2x km
and distance travelled by the second train = 2 (x + 5) km
According to the condition,
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 18
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 19

Question 23.
A steamer goes downstream from one point to another in 9 hours. It covers the same distance upstream in 10 hours. If the speed of the stream be 1 km/hr, find the speed of the steamer in still water and the distance between the ports.
Solution:
Time taken by a steamer downstream = 9 hours
and upstream = 10 hours Speed of steamer = 1 km/hr.
Let speed of the steamer = x km/h.
According to the condition :
9 (x + 1) = 10 (x – 1)
9x + 9 = 10x – 10 ⇒ 10x – 9x = 9 + 10
⇒ x = 19
∴  Speed of steamer in still water =19 km/h
and distance between two ports = 9 (a + 1) = 9 (19 + 1) = 9 x 20 = 180 km.

Question 24.
Bhagwanti inherited Rs. 12000.00 She invested part of it as 10% and the rest at 12%. Her annual income from these investments is Rs. 1280.00. How much did she invest at each rate ?
Solution:
Total investment = Rs. 12000.00
Rate of interest for first part = 10%
and for second part = 12%
Annual income = Rs. 1280.00
Let the investment for the first part = Rs. x
and second part = Rs. (12000 – x)
According to the condition :
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 20
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 21

Question 25.
Total investment = Rs. 12000.00 Rate of interest for first part = 10% and for second part = 12% Annual income = Rs. 1280.00 Let the investment for the first part = Rs. a and second part = Rs. (12000 – a) According to the condition :
Solution:
Let breadth of the rectangle = x cm
Then length = (x + 9) cm
∴ Area = length x breadth = x (x + 9) cm2
By increasing each length and breadth by 3 cm
The new length of the rectangle = x + 9 + 3
= (x + 12) cm
and breadth = (x + 3) cm
∴  Area = (x + 12) (x + 3)
According to the condition :
(x + 12) (x + 3) – a (x + 9) = 84
x2 + 3x + 12x + 36 – x2 – 9x = 84
⇒ 6a = 84 – 36 = 48 ⇒ x  = \(\frac { 48 }{ 6 }\) =8
∴  Length of the rectangle = a + 9 = 8 + 9 = 17 cm
and breadth =x = 8 cm.

Question 26.
The sum of the ages of Anup and his father is 100. When Anup is as old as his father now, he will be five times as old as his son Anuj is now. Anuj will be eight years older than Anup is now, when Anup is as old as his father. What are their ages now ?
Solution:
Sum of ages of Anup and his father =100 years
Let present age of Anup = x years
∴  Age of his father = (100 – x) years
∴  Age of Anuj = \(\frac { 100 – x  }{ 5 }\) years
and also Anuj’s age = (x + 8) years ….I
Anup becomes as old as his father is now
after (100 – 2x) years
∴ After (100 – 2x) years
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 22

Question 27.
A lady went shopping and spent half of what she had on buying hankies and gave a rupee to a begger waiting outside the shop. She spent half of what was left on a lunch and followed that up with a two rupee tip. She spent half of the remaining amount on a book and three rupees on bus fare. When she reached home, she found that she had exactly one rupee left. How much money did she start with ?
Solution:
Let the amount, a lady has in the beginning = Rs. x

RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 23
RD Sharma Class 8 Solutions Chapter 9 Linear Equations in One Variable Ex 9.4 24
Hope given RD Sharma Class 8 Solutions Linear Equations in One Variable Ex 9.4 are helpful to complete your math homework.

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RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B

RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B

These Solutions are part of RS Aggarwal Solutions Class 6. Here we have given RS Aggarwal Solutions Class 6 Chapter 10 Ratio, Proportion and Unitary Method Ex 10B.

Other Exercises

Question 1.
Solution:
(i) 4, 6, 8, 12
If it is in proportion, then
If ad = bc if 4 x 12 = 6 x 8
If 48 = 48
Which is true
∴ 4, 6, 8, 12 are in proportion
(ii) 7, 42, 13, 78
7 : 42 :: 13 : 78
If ad = bc if 7 x 78 = 42 x 13
If 546 = 546
Which is true
∴ 7, 42, 13, 78 are in proportion
(iii) 33, 121, 9, 96 or 33 : 121 :: 9 : 96
are in proportion
If ad = bc
If 33 x 96 = 121 x 9
If 3168 = 1089
Which is not true
∴ 33, 121,9, 96 are not in proportion
(iv) 22, 33, 42, 63 or 22 : 33 :: 42 : 63
are in proportion
If ad = bc
If 22 x 63 = 33 x 42
If 1386 = 1386
Which is true
∴ 22, 33, 42, 63 are in proportion
(v) 32, 48, 70, 210 or 32 : 48 :: 70 : 210
are in proportion
If ad = bc
If 32 x 210 = 48 x 70
If 6720 = 3360
Which is not true
∴ 32, 48, 70, 210 are not in proportion
(vi) 150, 200, 250, 300 or
150 : 200 :: 250 : 300 are in proportion
If ad = bc if 150 x 300 = 200 x 250
If 45000 = 50000
Which is not true
∴ 150, 200,250, 300 are not in proportion

Question 2.
Solution:
(i) We have 60 : 105 :: 84 : 147
Product of means = 105 x 84 = 8820
Product of extremes = 60 x 147 = 8820
∴ Product of means = Product of extremes
Hence 60 : 105 :: 84 : 147 is verified.
(ii) We have 91 : 104 :: 119 : 136
Product of means = 104 x 119 = 12376
Product of extremes = 91 x 136 = 12376
Product of means = Product of extremes
Hence 91 : 104 :: 119 : 136 is verified.
(iii) We have 108 : 72 :: 129 : 86
Product of means = 72 x 129 = 9288
Product of extremes = 108 x 86 = 9288
Product of means = Product of extremes
Hence 108 : 72 :: 129 : 86 is verified.
(iv) We have 39 : 65 :: 141 : 235
Product of means = 65 x 141 = 9165
Product of extremes = 39 x 235 = 9165
∴ Product of means = Product of extremes
Hence 39 : 65 :: 141 : 235 is verified.

Question 3.
Solution:
(i) We have 55 : 11 :: x : 6
Product of means = 11 × x = 11x
Product of extremes = 55 x 6 = 330
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B Q3.1
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B Q3.2

Question 4.
Solution:
(i) We have, 51 : 68 = \(\\ \frac { 51 }{ 68 } \)
= \(\\ \frac { 3 }{ 4 } \)
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B Q4.1
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B Q4.2
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B Q4.3

Question 5.
Solution:
(i) 25 cm : 1 m and Rs. 40 : Rs. 160
= \(\\ \frac { 25cm }{ 1000cm } \) = \(\\ \frac { 1 }{ 4 } \),
\(\\ \frac { Rs.40 }{ Rs.160 } \) = \(\\ \frac { 1 }{ 4 } \)
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B Q5.1
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B Q5.2
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B Q5.3

Question 6.
Solution:
Let the third term be x.
Then 51 : 68 :: x : 108
Now, product of means = x × 68
And, product of extremes = 51 × 108
x × 68 = 51 × 108
=> x = \(\\ \frac { 51\times 108 }{ 68 } \)
= 3 × 27 = 81
x = 81
Hence the third term of the given proportion is 81

Question 7.
Solution:
1st term =12, third term = 8 and fourth term = 14
Let 2nd term = x, then
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B Q7.1

Question 8.
Solution:
(i) The given numbers 48, 60, 75 are in
continued proportion if 48 : 60 :: 60 : 75.
Now, product of means = 60 x 60 = 3600
And, product of extremes = 48 x 75 = 3600
∴ Product of means = Product of extremes
So, 48 : 60 :: 60 : 75
Hence, the numbers 48, 60, 75 are in continued proportion.
(ii) The given numbers 36, 90, 225 are in
continued proportion of 36 : 90 :: 90 : 225
Now, product of means = 90 x 90 = 8100
And, product of extremes = 36 x 225 = 8100
∴ Product of means = Product of extremes
So, 36 : 90 :: 90 : 225
Hence, the numbers 36, 90, 225 are in continued proportion.
(iii)The given numbers 16, 84, 441 are in
continued proportion if 16 : 84 :: 84 : 441.
Now, product of means = 84 x 84 = 7056
And, product of extremes = 16 x 441 = 7056
Product of means = Product of extremes.
So, 16 : 845 :: 84 : 441
Hence 16, 84, 441 are in continued proportion.
(iv) The given numbers 27, 36, 48 are
in continued proportion if 27 : 36 :: 36 : 48
Now, product of means = 36 x 36 = 1296
And, product of extremes = 27 x 48 = 1296
∴ Product of means = Product of extremes.
So, 27 : 36 :: 36 : 48
Hence, the numbers 27, 36, 48 are in continued proportional.

Question 9.
Solution:
It is given that 9, x, x, 49 are in proportion, that is, 9 : x :: x : 49
∴ Product of means = Product of extremes
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B Q9.1

Question 10.
Solution:
Let the height of the pole be x metres.
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B Q10.1

Question 11.
Solution:
5 : 3 :: x : 6
RS Aggarwal Class 6 Solutions Chapter 10 Ratio, Proportion and Unitary Method Ex 10B Q11.1

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RS Aggarwal Class 6 Solutions Chapter 16 Triangles Ex 16A

RS Aggarwal Class 6 Solutions Chapter 16 Triangles Ex 16A

These Solutions are part of RS Aggarwal Solutions Class 6. Here we have given RS Aggarwal Solutions Class 6 Chapter 16 Triangles Ex 16A

Other Exercises

Question 1.
Solution:
A, B and C are three non-collinear points in a plane. AB, BC and CA are joined.
RS Aggarwal Class 6 Solutions Chapter 16 Triangles Ex 16A Q1.1
(i) The side opposite ∠C is AB
(ii) The angle opposite to the side BC is ∠A
(iii) The vertex opposite to the side CA is B
(iv) The side opposite to the vertex B is CA

Question 2.
Solution:
The measures of two angles of a triangle are 72° and 58°
But measure of three angles of a triangle is 180°
Third angle will be = 180 – (72° + 58°)
= 180° – 130°
= 50°

Question 3.
Solution:
Sum of three angles of a triangle = 180°
Ratio of three angles = 1 : 3 : 5
RS Aggarwal Class 6 Solutions Chapter 16 Triangles Ex 16A Q3.1
Hence, three angles are 20°, 60° and 100°
Ans.

Question 4.
Solution:
Sum of three angles of a right triangle = 180°
Sum of two acute angles = 180°- 90°
= 90°
Measure of one angle = 50°
Second acute angle = 90° – 50° = 40°
Ans.

Question 5.
Solution:
Let the measure of each of the equal angles be x°. Then,
x° + x°+ 110°= 180°
(Angle sum property of a triangle)
=> 2x°+110°= 180°
=> 2x° = 180° – 110° = 70°
=> \({ x }^{ O }={ \left( \frac { 70 }{ 2 } \right) }^{ O }={ 35 }^{ O }\)
The measure of each of the equal angles is 35°.

Question 6.
Solution:
Let the three angles of a triangle be ∠A, ∠B, ∠C. Then, ∠A = ∠B + ∠C
Adding ∠A to both sides, we get ∠A + ∠A = ∠A + ∠B + ∠C
=> 2 ∠A = 180°
(Angle sum property of a triangle)
=> ∠A = \({ \left( \frac { 180 }{ 2 } \right) }^{ O }={ 90 }^{ O }\)
One of the angles of the triangle is a right angle.
Hence, the triangle is a right triangle

Question 7.
Solution:
In a ∆ABC,
3∠A = 4∠B = 6∠C = 1 (say)
RS Aggarwal Class 6 Solutions Chapter 16 Triangles Ex 16A Q7.1

Question 8.
Solution:
(i) It is obtuse triangle.
(ii) It is acute triangle.
(iii) It is right triangle.
(iv) It is obtuse triangle.

Question 9.
Solution:
(i) It is an isosceles triangle as it has two equal sides.
(ii) It is an isosceles triangle as it has two equal sides.
(iii) It is a scalene triangle as its sides are different in length.
(iv) It is an equilateral triangle as its all sides are equal.
(v) It is an equilateral triangles as its angles are equal, so its sides will also be equal.
(vi) It is an isosceles triangle as its two base angles are equal, so its two sides are equal.
(vii) It is a scalene triangle as its angles are different, so its sides will also be different or unequal.

Question 10.
Solution:
In ∆ABC, D is a point on BC and AD is joined
Now we get triangles ∆ABC, ∆ABD and ∆ADC

Question 11.
Solution:
(i) No
(ii) No
(iii) Yes
(iv) No
(v) No
(vi) Yes.

Question 12.
Solution:
(i) three, three, three.
(ii) 180°
(iii) different
(iv) 60°
(v) equal
(vi) perimeter.

 

Hope given RS Aggarwal Solutions Class 6 Chapter 16 Triangles Ex 16A are helpful to complete your math homework.

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Value Based Questions in Science for Class 10 Chapter 15 Our Environment

Value Based Questions in Science for Class 10 Chapter 15 Our Environment

These Solutions are part of Value Based Questions in Science for Class 10. Here we have given Value Based Questions in Science for Class 10 Chapter 15 Our Environment

Question 1.
Why have the railway vendors been switching over from re-usable glasses to plastic cups, then clay cups and now paper cups while we stress greater role for renewable articles.
Answer:
There is no denying the fact that reusable articles are ecofriendly. However, they are also liable to get contaminated, especially when railway vendors do not have time and resources to sterilise them. Therefore, railways switched over to disposable articles. Reusable glasses were replaced with disposable plastic cups. However, plastic cups are not biodegradable. Their disposal posed a big problem. They could not be burnt as burning produced toxic gases. The dumping place became sites of breeding flies, mosquitoes and others. The practice was, therefore, discontinued and replaced by clay cups or kulhads. However, making lakhs of kulhads daily removed top fertile soil from several hundred acres of land. The clay cups also required dumping places. Ultimately, disposable paper cups have come to stay with the vendors. The waste cups are recyclable as well as can be burnt without causing problem of dumping.

More Resources

Question 2.
Hospital waste is not allowed to be mixed with municipal trash and garbage. Neither it is dumped separately. How is it disposed off and why ?
Answer:
Hospital waste is highly contaminated and can be a source of several diseases wherever it is dumped or disposed off. It also contains infected, cancerous and other waste tissues that can be source of several diseases. Therefore, hospital wastes are collected in separate bags and taken to incinerators for disposal. In incinerators the articles are burnt at 850°C under aerobic conditions. Smoke and grit are precipitated to avoid air pollution. Only ash and unburnt metallic materials are left. They are disposed off in land fills.

Question 3.
Most Australians develop skin problems as they grow old. Why ?
Answer:
Australia lies near Antarctica in the zone where ozone hole appears every year. More high energy ultraviolet rays (UV – B) reach the earth in the area of ozone hole. UV radiations cause skin cancers, mutations and cataracts besides reducing immunity. Therefore, most Australians come to have skin problems as they grow old.

Question 4.
Mahi’s father is a manufacturer who purchases raw materials from only one firm and sells the finished product to another single firm. While studying the difference between food chain and food web Mahi noted that his father is following a faulty practice which must be stopped. He also tried to convince his father about it.
What is the fault in the business of Mahi’s father and how has Mahi got this idea ?
Answer:
In a food chain, members of one trophic level are eaten by members of higher trophic level. A disease or scarcity due to drought that kills members of one trophic level, affects the population of both lower trophic level (very high number, glut) as well as higher trophic level (starvation and death). By anology, Mahi found that any problem in the supplier firm or purchaser firm will ruin his father’s business. Therefore, like a food web, there should be a few alternative sources of raw material supply as well as sale of finished products.
You plan to organise a compaign on “Harmful effects of smoking on human health” in your neighbourhood areas and guide them.

Question 5.
(a) List any three reasons that you will give to convince the people about harmful effects of smoking on human health.
(b) List any three values that are indicated with such approach. (CCE 2014)
Answer:
(a)

  1. Smoking causes cancer of oral cavity and lungs, bronchitis, emphysema, gastric ulcers and heart disease.
  2. Tobacco smoke is equally harmful to nonsmokers who live along with the smoker. They develop respiratory problems and CO toxicity.
  3. Smoking is a wasteful, rather harmful drain on the resources of the family.
  4. Smoke is irritant to nonsmokers.

(b) Values:

  1. To protect the residents from the harmful effect of smoking .
  2. It will educate your classmates and others in the compaign not to indulge in smoking despite peer pressure.
  3. Participants in the compaign will be able to spread the message to their families and acquaintances. Ecoclub of your school is organising a debate on the topic “Nature’s fury unleashed by human greed (Uttarakhand disaster) “.

Question 6.
(a) List three arguments that you will use to convince the audience that humans are responsible for this disaster.
(b) List three values that will be inculcated with this debate. (CCE 2014)
Answer:
(a) Nature’s Fury: Humans are responsible for excessive landslides and floods in the hilly areas due to following reasons :

  1. Building dams to store water and generate electricity. However, the geology of hills is usually unstable.
    Seepage from dams make the hills prone to excessive landslides and earthquakes.
  2. Hills attract a large number of tourists. Roads are build up and a great deal of construction activity is carried out along the roads to accomodate tourists.
  3. Trees are cut off for construction activity and roads. Debris of construction sites is often thrown into gorges and channels near the roads and buildings.
  4. A lot of garbage and other wastes are generated by tourists and the locals. However, there is no system for their proper disposal.

(b) Values:

  1. It is important to know the features of our environment and surroundings.
  2. No human activity should disturb the balance of nature.
  3. Trees are life line against disturbances in nature. They should not be felled unless protective measures have been taken.
  4. There should be proper and scientific method for disposal of wastes.
    You have been asked to talk on “Ozone layer and its protection” in the school assembly on ‘Envrionment Day’.

Question 7.
(a) Why should ozone layer be protected to save the environment ?
(b) List any two ways that you would stress in your talk to bring in awareness amongst your fellow friends that would also help in protection of ozone layer as well as envronment. (CBSE Delhi 2017)
Answer:
Ozone layer is present in the stratosphere roughtly 23-25 km above the equator and 10-16 km above the poles. It protects the earth by filtering out the harmful UV radiations,. However, due to release of ozone depleting substances (ODS), ozone layer has thinned out by 8% over the equator. A big hole appears every year in August-September over Antarctica. This has increased the level of UV-B radiations reaching the earth by 15-20%. These radiations are causing increased number of skin cancers, cataracts and reduced immunity in human beings. There is also increased incidence of blinding of animals, death of young ones, reduced photosynthesis, higher number of mutations and damage to articles.
The remedy lies in banning the use of ozone depleting substances like halons and chlorofluorocarbons (CFCs).
All the classmates and the public in general should be made aware of the consequences of depletion of ozone layer, causes of depletion as well other aspects of degradation of environment. This could be done by

  1. Arranging poster making competition as well as exhibition highlighting the effects of ozone layer depletion,
  2. Conducting street plays about the harmful effects of our tampering with envronment and how to remedy the situation.

Hope given Value Based Questions in Science for Class 10 Chapter 15 Our Environment are helpful to complete your science homework.

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RS Aggarwal Class 6 Solutions Chapter 15 Polygons Ex 15

RS Aggarwal Class 6 Solutions Chapter 15 Polygons Ex 15

These Solutions are part of RS Aggarwal Solutions Class 6. Here we have given RS Aggarwal Solutions Class 6 Chapter 15 Polygons Ex 15

Question 1.
Solution:
(a), (b), (d) and (f) are simple closed figures.

Question 2.
Solution:
(a), (b) and (c) are polygons.

Question 3.
Solution:
(i) two
(ii) triangle
(iii) quadrilateral
(iv) 3, 3
(v) 4, 4
(vi) closed figure.

 

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RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4

RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4

These Solutions are part of RD Sharma Class 8 Solutions. Here we have given RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4

Other Exercises

Question 1.
5x3 – 15x2 + 25x by 5x
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 1

Question 2.
4z3 + 6z2-zby \(\frac { -1 }{ 2 }\) z
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 2

Question 3.
9x2y – 6xy + 12xy2 by \(\frac { -3 }{ 2 }\) xy
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 3
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 4

Question 4.
3x2y2 + 2x2y + 15xy by 3xy
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 5

Question 5.
x2 + 7x + 12 by x + 4
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 6

Question 6.
4y4 + 3y + \(\frac { -1 }{ 2 }\) by 2y + 1
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 7
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 8

Question 7.
3x3 + 4x2 + 5x + 18 by x + 2
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 9

Question 8.
14x2 – 53x + 45 by 7a – 9
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 10

Question 9.
-21 + 71x – 31x2 – 24ax3 by 3 – 8ax
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 11
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 12

Question 10.
3y4 – 3y3 – 4y2 – 4y by y2 – 2y
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 13

Question 11.
2y5 + 10y4 + 6y3 + y2 + 5y + 3 by 2y3 + 1
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 14
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 15

Question 12.
x4 – 2x3 + 2x2 + x + 4 by x2 + x + 1
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 16

Question 13.
m3 – 14m2 + 37m – 26 by m2 – 12m + 13
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 17

Question 14.
x4 + x2 + 1 by x2 + x + 1
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 18
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 19

Question 15.
x5 + x4 + x3+x2 + x+ 1 by x3 + 1
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 20

Divide each of the following and find the quotient and remainder :

Question 16.
14x3 – 5x2 + 9x -1 by 2x – 1
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 21

Question 17.
6x3 – x2 – 10x – 3 by 2x – 3
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 22
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 23

Question 18.
6x3+ 11x2 – 39x – 65 by 3x2 + 13x + 13
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 24

Question 19.
30a4 + 11a3-82a2– 12a + 48 by 3a2 + 2a- 4
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 25

Question 20.
9x4 – 4x2 + 4 by 3x2 – 4x + 2
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 26

Question 21.
Verify division algorithm i.e., Dividend = Divisor * Quotient + Remainder, in each of the following. Also, write the quotient and remainder :
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 27
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 28
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 29
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 30
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 31
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 32
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 33

Question 22.
Divide 15y4 + 16y3 + \(\frac { 10 }{ 3 }\) y – 9y2 – 6 by 3y – 2
Write down the co-efficients of the terms in the quotient.
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 34
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 35

Question 23.
Using division of polynomials state whether.
(i) x + 6 is a factor of x2 – x – 42
(ii) 4x – 1 is a factor of 4x2 – 13x – 12
(iii) 2y – 5 is a factor of 4y4 – 10y3 – 10y2 + 30y -15
(iv) 3y + 5 is a factor of 6y5 + 15y + 16y + 4y+ 10y – 35
(v) z2 + 3 is a factor of z5– 9z
(vi) 2x2 – x + 3 is a factor of 60x5-x4 + 4x3 – 5x2 -x- 15
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 36
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 37
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 38
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 39
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 40
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 41

Question 24.
Find the value of ‘a’, if x + 2 is a factor of 4x4 + 2x3 – 3x2 + 8x + 5a.
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 42
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 43

Question 25.
What must be added to x4 + 2x3 — 2x2 + x – 1 so that the resulting polynomial is exactly divisible by x2 + 2x – 3.
Solution:
RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 44

Hope given RD Sharma Class 8 Solutions Chapter 8 Division of Algebraic Expressions Ex 8.4 are helpful to complete your math homework.

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HOTS Questions for Class 10 Science Chapter 15 Our Environment

HOTS Questions for Class 10 Science Chapter 15 Our Environment

These Solutions are part of HOTS Questions for Class 10 Science. Here we have given HOTS Questions for Class 10 Science Chapter 15 Our Environment

Question 1.
Study the figure. What does it depict ?
HOTS Questions for Class 10 Science Chapter 15 Our Environment image - 1
Answer:
It is representation of movement of energy and matter in the biosphere.
Energy flow is unidirectional while matter is repeatedly recycled.

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Question 2.
Which trophic level eats nothing and which one is not eaten.
Answer:
Eats Nothing: Producers.
Not Eaten: Top carnivores.

Question 3.
What is the reason that a food chain consists of only 3-5 steps ? (CCE 2011)
Answer:
As per 10% law of Lindeman (1942), the energy available decreases by 90% with the rise of trophic level. 2000 J of energy available at the producer or T1 level will provide only 2 J of energy to second order carnivores (T4).
Therefore, an ecosystem cannot have food chains of several steps.

Question 4.
Describe how decomposers facilitate recycling of matter in order to maintain balance in the ecosystem. (CBSE Foreign 2010)
Answer:
Decomposers act on organic or biodegradable wastes by secreting digestive enzymes over them. Organic waste is broken down into soluble simpler substances. Decomposers pick up the simple organic substances for their own use leaving the inorganic substances. The phenomenon is called mineralisation. Minerals released from decaying organic matter become available to plants for reuse. Decomposers, therefore, help in recycling of minerals and maintain the balance in the ecosystem.

Hope given HOTS Questions for Class 10 Science Chapter 15 Our Environment are helpful to complete your science homework.

If you have any doubts, please comment below. Learn Insta try to provide online science tutoring for you.